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Nickel Plating

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  • Nickel Plating

    Anyone out there have experience with electrolytic plating? My first attempt at electrolytic nickel plating came out looking more like copper plating, and I'm trying to figure out why. I made the nickel electrolyte from 30% vinegar (ph about 4 or 5), suspending two pieces of nickel from copper wires in the vinegar, and putting a low voltage/current between the nickel electrodes. After a few hours, the electrolyte turned not blue, but blue-green. I then tried to plate a steel part, glass beaded, degreased, and etched in dilute muriatic acid, using one of the pieces of nickel as a positive electrode, and the steel part as the negative. After a half hour at 3.3 volts and 0.1 amps, the part was nicely plated, but had a definite copper color.

    The only source of copper in this set-up is the wires used to suspend the electrodes and the work in the electrolyte. Perhaps the electrolyte is contaminated with copper. Perhaps the plating operation plates copper in preference to nickel. Both problems would be fixed by using something other than copper wire. I have stainless steel safety wire. Would that work?

    All information/advice welcome. Thanks.

  • #2
    I know nothing about this stuff, but maybe keep the copper out of (above) the solution?
    "A machinist's (WHAP!) best friend (WHAP! WHAP!) is his hammer. (WHAP!)" - Fred Tanner, foreman, Lunenburg Foundry and Engineering machine shop, circa 1979

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    • #3
      You can buy diy nickel plating solutions, they might work better.

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      • #4
        Did your copper wires from the initial solution preparation touch the solution? Sounds like you've got copper contamination. The initial solution should not be bluish at all, rather it should be pure green.

        When preparing your initial plating solution only partially suspend the nickel electrodes, you need to keep the copper wire out of the solution completely.

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        • #5
          Nickel plates "better" over a copper plate layer.
          That's the extent of my knowledge. Was a customer of plating companies, various finishes, zinc, yellow, zinc, hot dip galv., chrome (rarely), Cadmium and Nickel.

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          • #6
            You could use nickel plated wire. Plenty out there for electronics.

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            • #7
              I don't see the point of the initial Ni - Ni electrolysis. without a specific Ni salt solution I think you are just electrolysing water with the acid causing it to be dissociatec intot OH and H ions to facilitate this. In doing this you have probably just put a thin oxide layer on the metal that has a brownish colour.

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              • #8
                Yes--copper contamination. Don't let the copper go into the bath, or use nickel wire.

                The initial electrolytic step "charges" the bath with nickle ions, which gives it the green color. Starting with a real nickle bath would work better.

                Ed
                For just a little more, you can do it yourself!

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                • #9
                  Go on ebay and buy a couple of those flat 1x6" nickel anodes. Make your own watts bath from white vinegar and a little salt to enhance conductivity. Let the nickle anodes plate in the bath for a while perhaps 12 hours until the solution turns green.

                  If your parts to be plated are small as in you can hold a few of them in your hand, you don't need much power. 1 quart glass jar for your container size using a cell phone charger for the power supply *That's 5 volts and 1.5 amps. + to one or two nickle anodes, - on the workload.

                  As you found out, let only the nickel anodes have contact in the bath. You can submerge copper wire in the bath that supports the workload as that too will be plated and not transfer copper to the anode or the bath.

                  A coating of nickel on something like a 1/2 diameter 4 inch long part of steel takes maybe one minute.Plating requires absolutely clean parts.
                  Note that plating baths have zero tolerance for any contamination. Parts must be ultra clean before you immerse them.
                  Last edited by I make chips; 01-23-2021, 11:43 AM.

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                  • #10
                    We rhodium plate at work in a sulfuric acid bath. At $15,000 an ounce, contamination of copper or worse, iron, is a huge concern. We use copper wires to hook the items, but pre-plate those first with rhodium to stop contamination of the main bath.

                    As above perfectly clean is essential. After polishing, we clean in an ultrasonic bath, then steam clean, then washed in lye, then a couple of baths of deionized water before plating
                    Last edited by lakeside53; 01-23-2021, 12:05 PM.

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                    • #11
                      Originally posted by I make chips View Post
                      ...Make your own watts bath from white vinegar and a little salt to enhance conductivity...
                      Washing soda is better for your lungs than salt. Or does washing soda not work with nickel? (I have only done zinc plating.)

                      Location: Northern WI

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                      • #12
                        Originally posted by mickeyf View Post
                        I know nothing about this stuff, but maybe keep the copper out of (above) the solution?
                        I don't know much about plating either but would it be easier to buy the nickel plating solution rather than trying to unplate / dissolve it off of one piece and plate it to another in the same operation ? That's what it sounds like you trying to do, to me anyway.

                        JL................

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                        • #13
                          It's been years since I dabbled in electroplating, but that was more towards electroforming small molds.

                          My understanding of plating is that the electrolyte solution needs to be a metallic salt, in your
                          case it would be nickle sulfate or nickle chloride the transfer of metal comes from the solution
                          not the anode, which is there to replenish what is drawn out of the solution to a degree.

                          You may want to locate a copy of The Electroplaters Handbook by C.W. Ammen I found it very useful.


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                          • #14
                            We did a lot of nickel at work
                            Not only super clean, But never use any chlorinated cutting oils or coolants !
                            A word about thickness of plate.
                            For a general cosmetic coating .0002 of nickel works and is considered a"flash " Coating
                            To protect parts, a .0005 " coating is good , and for a wear surface .001" thick
                            To check coating thickness , use safety razor blades ( if you can find them) They are incredible consistent in thickness
                            Measure one and then place it in the bath with the part and when you remove it , remeasure the thickness and the plating will be 1/2 of the difference .
                            Reflecting a single side . Of course if you are doing a round shaft, just measure it closely beforehand

                            Rich
                            Green Bay, WI

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                            • #15
                              I worked for a company where we copper plated both ends of a nichrome ribbon. You couldn’t plate the copper directly on the nichrome, a flash nickel plate was needed first. Our setup was really crude but the results were very good.

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